<?php
/**
 * Created by PhpStorm.
 * User: lius
 * Date: 2017/7/15
 * Time: 12:51
 * From: 等英博客出品 http://www.waitig.com
 */
/**
 * Class Name: WP_Bootstrap_Navwalker
 * Plugin Name: WP Bootstrap Navwalker
 * Plugin URI:  https://github.com/wp-bootstrap/wp-bootstrap-navwalker
 * Description: A custom WordPress nav walker class to implement the Bootstrap 3 navigation style in a custom theme using the WordPress built in menu manager.
 * Author: Edward McIntyre - @twittem, WP Bootstrap
 * Version: 2.0.5
 * Author URI: https://github.com/wp-bootstrap
 * GitHub Plugin URI: https://github.com/wp-bootstrap/wp-bootstrap-navwalker
 * GitHub Branch: master
 * License: GPL-3.0+
 * License URI: http://www.gnu.org/licenses/gpl-3.0.txt
 */
/* Check if Class Exists. */
if (!class_exists('WP_Bootstrap_Navwalker')) {
    /**
     * WP_Bootstrap_Navwalker class.
     *
     * @extends Walker_Nav_Menu
     */
    class WP_Bootstrap_Navwalker extends Walker_Nav_Menu
    {
        /**
         * Start Level.
         *
         * @see Walker::start_lvl()
         * @since 3.0.0
         *
         * @access public
         * @param mixed $output Passed by reference. Used to append additional content.
         * @param int $depth (default: 0) Depth of page. Used for padding.
         * @param array $args (default: array()) Arguments.
         * @return void
         */
        public function start_lvl(&$output, $depth = 0, $args = array())
        {
            $indent = str_repeat("\t", $depth);
            $output .= "\n$indent<ul role=\"menu\" class=\" dropdown-menu\" >\n";
        }

        /**
         * Start El.
         *
         * @see Walker::start_el()
         * @since 3.0.0
         *
         * @access public
         * @param mixed $output Passed by reference. Used to append additional content.
         * @param mixed $item Menu item data object.
         * @param int $depth (default: 0) Depth of menu item. Used for padding.
         * @param array $args (default: array()) Arguments.
         * @param int $id (default: 0) Menu item ID.
         * @return void
         */
        public function start_el(&$output, $item, $depth = 0, $args = array(), $id = 0)
        {
            $indent = ($depth) ? str_repeat("\t", $depth) : '';
            /**
             * Dividers, Headers or Disabled
             * =============================
             * Determine whether the item is a Divider, Header, Disabled or regular
             * menu item. To prevent errors we use the strcasecmp() function to so a
             * comparison that is not case sensitive. The strcasecmp() function returns
             * a 0 if the strings are equal.
             */
            if (0 === strcasecmp($item->attr_title, 'divider') && 1 === $depth) {
                $output .= $indent . '<li role="presentation" class="divider">';
            } elseif (0 === strcasecmp($item->title, 'divider') && 1 === $depth) {
                $output .= $indent . '<li role="presentation" class="divider">';
            } elseif (0 === strcasecmp($item->attr_title, 'dropdown-header') && 1 === $depth) {
                $output .= $indent . '<li role="presentation" class="dropdown-header">' . esc_attr($item->title);
            } elseif (0 === strcasecmp($item->attr_title, 'disabled')) {
                $output .= $indent . '<li role="presentation" class="disabled"><a href="#">' . esc_attr($item->title) . '</a>';
            } else {
                $value = '';
                $class_names = $value;
                $classes = empty($item->classes) ? array() : (array)$item->classes;
                $classes[] = 'menu-item-' . $item->ID;
                $class_names = join(' ', apply_filters('nav_menu_css_class', array_filter($classes), $item, $args));
                if ($args->has_children) {
                    $class_names .= ' dropdown';
                }
                if (in_array('current-menu-item', $classes, true)) {
                    $class_names .= ' active';
                }
                $class_names = $class_names ? ' class="' . esc_attr($class_names) . '"' : '';
                $id = apply_filters('nav_menu_item_id', 'menu-item-' . $item->ID, $item, $args);
                $id = $id ? ' id="' . esc_attr($id) . '"' : '';
                $output .= $indent . '<li itemscope="itemscope" itemtype="https://www.schema.org/SiteNavigationElement"' . $id . $value . $class_names . '>';
                $atts = array();
                if (empty($item->attr_title)) {
                    $atts['title'] = !empty($item->title) ? strip_tags($item->title) : '';
                } else {
                    $atts['title'] = $item->attr_title;
                }
                $atts['target'] = !empty($item->target) ? $item->target : '';
                $atts['rel'] = !empty($item->xfn) ? $item->xfn : '';
                // If item has_children add atts to a.
                if ($args->has_children && 0 === $depth) {
                    $atts['href'] = '#';
                    $atts['data-toggle'] = 'dropdown';
                    $atts['class'] = 'dropdown-toggle';
                    $atts['aria-haspopup'] = 'true';
                } else {
                    $atts['href'] = !empty($item->url) ? $item->url : '';
                }
                $atts = apply_filters('nav_menu_link_attributes', $atts, $item, $args);
                $attributes = '';
                foreach ($atts as $attr => $value) {
                    if (!empty($value)) {
                        $value = ('href' === $attr) ? esc_url($value) : esc_attr($value);
                        $attributes .= ' ' . $attr . '="' . $value . '"';
                    }
                }
                $item_output = $args->before;
                /*
                 * Glyphicons/Font-Awesome
                 * ===========
                 * Since the the menu item is NOT a Divider or Header we check the see
                 * if there is a value in the attr_title property. If the attr_title
                 * property is NOT null we apply it as the class name for the glyphicon.
                 */
                if (!empty($item->attr_title)) {
                    $pos = strpos(esc_attr($item->attr_title), 'glyphicon');
                    if (false !== $pos) {
                        $item_output .= '<a' . $attributes . '><span class="glyphicon ' . esc_attr($item->attr_title) . '" aria-hidden="true"></span>&nbsp;';
                    } else {
                        $item_output .= '<a' . $attributes . '><i class="fa ' . esc_attr($item->attr_title) . '" aria-hidden="true"></i>&nbsp;';
                    }
                } else {
                    $item_output .= '<a' . $attributes . '>';
                }
                $item_output .= $args->link_before . apply_filters('the_title', $item->title, $item->ID) . $args->link_after;
                $item_output .= ($args->has_children && 0 === $depth) ? ' <span class="caret"></span></a>' : '</a>';
                $item_output .= $args->after;
                $output .= apply_filters('walker_nav_menu_start_el', $item_output, $item, $depth, $args);
            } // End if().
        }

        /**
         * Traverse elements to create list from elements.
         *
         * Display one element if the element doesn't have any children otherwise,
         * display the element and its children. Will only traverse up to the max
         * depth and no ignore elements under that depth.
         *
         * This method shouldn't be called directly, use the walk() method instead.
         *
         * @see Walker::start_el()
         * @since 2.5.0
         *
         * @access public
         * @param mixed $element Data object.
         * @param mixed $children_elements List of elements to continue traversing.
         * @param mixed $max_depth Max depth to traverse.
         * @param mixed $depth Depth of current element.
         * @param mixed $args Arguments.
         * @param mixed $output Passed by reference. Used to append additional content.
         * @return null Null on failure with no changes to parameters.
         */
        public function display_element($element, &$children_elements, $max_depth, $depth, $args, &$output)
        {
            if (!$element) {
                return;
            }
            $id_field = $this->db_fields['id'];
            // Display this element.
            if (is_object($args[0])) {
                $args[0]->has_children = !empty($children_elements[$element->$id_field]);
            }
            parent::display_element($element, $children_elements, $max_depth, $depth, $args, $output);
        }

        /**
         * Menu Fallback
         * =============
         * If this function is assigned to the wp_nav_menu's fallback_cb variable
         * and a menu has not been assigned to the theme location in the WordPress
         * menu manager the function with display nothing to a non-logged in user,
         * and will add a link to the WordPress menu manager if logged in as an admin.
         *
         * @param array $args passed from the wp_nav_menu function.
         */
        public static function fallback($args)
        {
            if (current_user_can('edit_theme_options')) {
                /* Get Arguments. */
                $container = $args['container'];
                $container_id = $args['container_id'];
                $container_class = $args['container_class'];
                $menu_class = $args['menu_class'];
                $menu_id = $args['menu_id'];
                if ($container) {
                    echo '<' . esc_attr($container);
                    if ($container_id) {
                        echo ' id="' . esc_attr($container_id) . '"';
                    }
                    if ($container_class) {
                        echo ' class="' . sanitize_html_class($container_class) . '"';
                    }
                    echo '>';
                }
                echo '<ul';
                if ($menu_id) {
                    echo ' id="' . esc_attr($menu_id) . '"';
                }
                if ($menu_class) {
                    echo ' class="' . esc_attr($menu_class) . '"';
                }
                echo '>';
                echo '<li><a href="' . esc_url(admin_url('nav-menus.php')) . '" title="">' . esc_attr('Add a menu', '') . '</a></li>';
                echo '</ul>';
                if ($container) {
                    echo '</' . esc_attr($container) . '>';
                }
            }
        }
    }
} // End if().